The present invention relates to devices used for moving a flexible covering between an open and a covering relation to the open top of the load-carrying body of a truck. The necessity for covers of this nature has resulted from local and state regulations which require open top trucks which haul materials such as sand, gravel, land fill, etc. to cover the loads. Loads of this nature have constituted a hazard to following automobiles and motorcyclists due to the fact that the air currents created by rapid movements of the trucks generally result in such materials flying into the following traffic, sometimes resulting in damages such as broken windshields.
Various types of cover mechanisms have been developed and patented. However, the widths of most of the covers approximate the widths of the open tops of the dump trucks and as most trucks generally are loaded to their maximum capacity for economic reasons, the resulting hump loads generally draw the covers upwardly, exposing the side edges of the loaded materials. Attempts at solving this problem have resulted in a plurality of the tie-down lines or ropes, fixed in a spaced relation along the two side edges of the cover. The free ends of the tie downs are normally tied to projections along the sides of the truck body.
A majority of the truck body covers of this nature, now in use, are convolutely wound on a roller over the cab protector when in a retracted condition. As a result, the covers are transversely sized to the roller widths which are generally sized to the width of the truck body.